Method of transmitting at least one sub-packet based on feedback information in a wireless communication system

ABSTRACT

A method of transmitting subsequent sub-packets in a wireless communication system using a hybrid automatic request (HARQ) technique is disclosed. The method includes receiving feedback information from at least one receiving end, transmitting a transmit packet via at least one overhead channel, wherein the transmit packet includes information on carrier and antenna combination selected for subsequent transmission, and transmitting at least one sub-packet according to the selected carrier and antenna combination.

This application claims the benefit of U.S. Provisional Application No.60/765,448, filed on Feb. 3, 2006, U.S. Provisional Application No.60/765,487, filed on Feb. 3, 2006, and U.S. Provisional Application No.60/775,022, filed on Feb. 17, 2006, which are hereby incorporated byreference,

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of transmitting sub-packets,and more particularly, to a method of transmitting at least onesub-packet based on feedback information in a wireless communicationsystem. Although the present invention is suitable for a wide scope ofapplications, it is particularly suitable for transmitting sub-packetsassociated with hybrid automatic request using feedback informationwhich can be transmitted based on various means.

2. Discussion of the Related Art

In a wireless communication environment, a transmitting end send pilotor pilot signals to a receiving end. In response, the receiving endsends feedback information on the channels through which the pilotsignals were transmitted. Based on this feedback, the transmitting endtransmits data effectively and efficiently.

However, there is no guarantee that the data (also referred to as datapackets or packets) are received accurately by the receiving end.Moreover, there is no guarantee that the transmitting end transmittedthe packets effectively and efficiently.

Today, users of wireless communication enjoy freedom of mobility. Thatis, the user with a mobile terminal is able to travel from one place toanother while talking to someone without losing connection. Often times,a user can move from one service coverage area to another servicecoverage area (e.g., from one cell/sector to another cell/sector). Insuch a situation, the user can continue talking on his/her mobileterminal even in cell edge areas through proper scheduling of transmitpower from a base station.

To address the fast changing wireless communication environment, it isimportant that a more effective and efficient ways of transmitting datawhen the data is not accurately received by the receiving end. Further,it is important for the feedback information to provide more detailedinformation so that the transmitting end can make better datatransmission.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a method oftransmitting at least one sub-packet based on feedback information in awireless communication system that substantially obviates one or moreproblems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a method transmittingsubsequent sub-packets in a wireless communication system using a hybridautomatic request (HARQ) technique.

Another object of the present invention is o provide a of transmittingfeedback information in a wireless communication system.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, amethod of transmitting subsequent sub-packets in a wirelesscommunication system using a hybrid automatic request (HARQ) techniqueincludes receiving feedback information from at least one receiving end,transmitting a transmit packet via at least one overhead channel,wherein the transmit packet includes information on carrier and antennacombination selected for subsequent transmission, and transmitting atleast one sub-packet according to the selected carrier and antennacombination.

In another aspect of the present invention, a method or transmittingfeedback information in a wireless communication system includestransmitting the feedback information to at least one transmitting end,wherein the feedback information includes an indication to a selectionof a combination in a sub-active set.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings;

FIG. 1 illustrates wireless communication network architecture;

FIG. 2A illustrates a COMA spreading and de-spreading process;

FIG. 2B illustrates a COMA spreading and de-spreading process usingmultiple spreading sequences;

FIG. 3 illustrates a data link protocol architecture layer for acdma2000 wireless network;

FIG. 4 illustrates cdma2000 call processing;

FIG. 5 illustrates the cdma2000 initialization state;

FIG. 6 illustrates the cdma2000 system access state;

FIG. 7 illustrates a conventional cdma2000 access attempt;

FIG. 8 illustrates a conventional cdma2000 access sub-attempt;

FIG. illustrates the conventional cdma2000 system access state usingslot offset;

FIG. 10 illustrates a comparison of cdma2000 for 1x and 1xEV-DO;

FIG. 11 illustrates a network architecture layer for a 1xEV-DO wirelessnetwork;

FIG. 12 illustrates 1xEV-DO default protocol architecture;

FIG. 13 illustrates 1xEV-DO non-default protocol architecture;

FIG. 14 illustrates 1xEV-DO session establishment;

FIG. 15 illustrates 1xEV-DO connection layer protocols

FIG. 16 is an exemplary diagram illustrating transmission of pilotsignal and feedback intimation between a single transmitting end and asingle receiving end;

FIG. 17 is art exemplary diagram illustrating handover situation;

FIG. 18 is an exemplary diagram illustrating selection of a pilot by thereceiving end for multiple sectors;

FIG. 19 is another exemplary diagram illustrating selection of a pilotby the receiving end for multiple sectors; and

FIG. 20 is an exemplary diagram illustrating selection of a pilot by thereceiving end for a single sector.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

Referring to FIG. 1, a wireless communication network architecture 1 isillustrated. A subscriber uses a mobile station (MS) 2 to access networkservices. The MS 2 may be a portable communications unit, such as ahand-held cellular phone, a communication unit installed in a vehicle,or a fixed-location communications unit.

The electromagnetic waves for the MS 2 are transmitted by the BaseTransceiver System (BTS) 3 also known as node 13. The BTS 3 consists ofradio devices such as antennas and equipment for transmitting andreceiving radio waves. The BS 6 Controller (BSC) 4 receives thetransmissions from one or more BTS's. The BSC 4 provides control andmanagement of the radio transmissions from each BTS 3 by exchangingmessages with the BTS and the Mobile Switching Center (MSC) 5 orInternal IF Network. The BTS's 3 and BSC 4 are part of the BS 6 (BS) 6.

The BS 6 exchanges messages with and transmits data to a CircuitSwitched Core Network (CSCN) 7 and Packet Switched Core Network (PSCN)8. The CSCN 7 provides traditional voice communications and the PSCN 8provides Internet applications and multimedia services.

The Mobile Switching Center (MSC) 5 portion of the CSCN 7 providesswitching for traditional voice communications to and from a MS 2 andmay store information to support these capabilities. The MSC 2 may beconnected to one of more BS's 6 as well as other public networks, forexample a Public Switched Telephone Network (PSTN) (not shown) orIntegrated Services Digital Network (ISDN) (not shown). A VisitorLocation Register (VLR) 9 is used to retrieve information for handlingvoice communications to or from a visiting subscriber. The VLR 9 may bewithin the MSC 5 and may serve more than one MSC.

A user identity is assigned to the Home Location Register (HLR) 10 ofthe CSCN 7 for record purposes such as subscriber information, forexample Electronic Serial Number (ESN), Mobile Directory Number (MDR),Profile Information, Current Location, and Authentication Period. TheAuthentication Center (AC) 11 manages authentication information relatedto the MS 2. The AC 11 may be within the HLR 10 and may serve more thanone HLR. The interface between the MSC 5 and the HLR/AC 10, 11 is anIS-41 standard interface 18.

The Packet data Serving Node (PDSN) 12 portion of the PSCN 8 providesrouting for packet data traffic to and from MS 2. The PDSN 12establishes, maintains, and terminates link layer sessions to the MS 2's2 and may interface with one of more BS 6 and one of more PSCN 8.

The Authentication, Authorization and Accounting (AAA) 13 Serverprovides Internet Protocol authentication, authorization and accountingfunctions related to packet data traffic. The Home Agent (HA) 14provides authentication of MS 2 IP registrations, redirects packet datato and from the Foreign Agent (FA) 15 component of the PDSN 8, andreceives provisioning information for users from the AAA 13. The HA 14may also establish, maintain, and terminate secure communications to thePDSN 12 and assign a dynamic IP address. The PDSN 12 communicates withthe AAA 13, HA 14 and the Internet 16 via an Internal IP Network.

There are several types of multiple access schemes, specificallyFrequency Division Multiple Access (FDMA), Time Division Multiple Access(TDMA) and Code Division Multiple Access (CDMA). In FDMA, usercommunications are separated by frequency, for example, by using 30 KHzchannels. In TDMA, user communications are separated by frequency andtime, for example, by using 30 KHz channels with 6 timeslots. In CDMA,user communications are separated by digital code.

In CDMA, All users on the same spectrum, for example, 1.25 MHz. Eachuser has a unique digital code identifier and the digital codes separateusers to prevent interference.

A CDMA signal uses many chips to convey a single bit of information.Each user has a unique chip pattern, which is essentially a codechannel. In order to recover a bit, a large number of chips areintegrated according to a user's known chip pattern. Other user's codepatterns appear random and are integrated in a self-canceling mannerand, therefore, do not disturb the bit decoding decisions made accordingto the user's proper code pattern.

Input data is combined with a fast spreading sequence and transmitted asa spread data stream. A receiver uses the same spreading sequence toextract the original data. FIG. 2A illustrates the spreading andde-spreading process. As illustrated in FIG. 2B, multiple spreadingsequences may be combined to create unique, robust channels.

A Walsh code is one type of spreading sequence. Each Walsh code is 64chips long and is precisely orthogonal to all other Walsh codes. Thecodes are simple to generate and small enough to be stored in read onlymemory (ROM).

A short PN code is another type of spreading sequence. A short PN codeconsists of two PN sequences (I and Q), each of which is 32,768 chipslong and is generated in similar, but differently tapped 15-bit shiftregisters. The two sequences scramble the information on the I and Qphase channels.

A long PN code is another type of spreading sequence. A long PN code isgenerated in a 42-bit register and is more than 40 days long, or about4×10¹³ chips long. Due to its length, a long PN code cannot be stored inROM in a terminal and, therefore, is generated chip-by-chip.

Each MS 2 codes its signal with the PN long code and a unique offset, orpublic long code mask, computed using the long PN code ESN of 32-bitsand 10 bits set by the system. The public long code mask produces aunique shift. Private long code masks may be used to enhance privacy.When integrated over as short a period as 64 chips, MS 2 with differentlong PN code offsets will appear practically orthogonal.

CDMA communication uses forward channels and reverse channels. A forwardchannel is utilized for signals from a BTS 3 to a MS 2 and a reversechannel is utilized for signals from a MS to a BTS.

A forward channel uses its specific assigned Walsh code and a specificPN offset for a sector, with one user able to have multiple channeltypes at the same time. A forward channel is identified by its COMA RFcarrier frequency, the unique short code PN offset of the sector and theunique Walsh code of the user. CDMA forward channels include a pilotchannel, sync channel, paging channels and traffic channels.

The pilot channel is a “structural beacon” which does not contain acharacter stream, but rather is a timing sequence used for systemacquisition and as a measurement device during handoffs. A pilot channeluses Walsh code 0.

The sync channel carries a data stream of system identification andparameter information used by MS 2 during system acquisition. A syncchannel uses Walsh code 32.

There may be from one to seven paging channels according to capacityrequirements. Paging channels carry pages, system parameter informationand call setup orders. Paging channels use Walsh codes 1-7.

The traffic channels are assigned to individual users to carry calltraffic. Traffic channels use any remaining Walsh codes subject tooverall capacity as limited by noise.

A reverse channel is utilized for signals front a MS 2 to a BTS 3 anduses a Walsh code and offset of the long PN sequence specific to the MS,with one user able to transmit multiple types of channelssimultaneously. A reverse channel is identified by its CDMA RF carrierfrequency and the unique long code PN Offset of the individual MS 2.Reverse channels include traffic channels and access channels.

Individual users use traffic channels during actual calls to transmittraffic to the BTS 3. A reverse traffic channel is basically auser-specific public or private long code Mask and there are as manyreverse traffic channels as there are CDMA terminals.

An MS 2 not yet involved in a call uses access channels to transmitregistration requests, call setup requests, page responses, orderresponses and other signaling information. An access channel isbasically a public long code offset unique to a BTS 3 sector. Accesschannels are paired with paging channels, with each paging channelhaving up to 32 access channels.

CDMA communication provides many advantages. Some of the advantages arevariable rate vocoding and multiplexing, power control, use of RAKEreceivers and soft handoff.

CDMA allows the use of variable rate vocoders to compress speech, reducebit rate and greatly increase capacity. Variable rate vocoding providesfull hit rate during speech, low data rates during speech pauses,increased capacity and natural sound. Multiplexing allows voice,signaling and user secondary data to be mixed in CDMA frames.

By utilizing forward power control, the BTS 3 continually reduces thestrength of each user's forward baseband chip stream. When a particularMS 2 experiences errors on the forward link, more energy is requestedand a quick boost of energy is supplied after which the energy is againreduced.

Using a RAKE receiver allows a MS 2 to use the combined outputs of thethree traffic correlators, or “RAKE fingers,” every frame, Each RAKEfinger can independently recover a particular PN Offset and Walsh code.The fingers may be targeted on delayed multipath reflections ofdifferent BTS's 3, with a searcher continuously checking pilot signals.

The MS 2 drives soft handoff. The MS 2 continuously checks availablepilot signals and reports to the BTS 3 regarding the pilot signals itcurrently sees. The BTS 3 assigns up to a maximum of six sectors and theMS 2 assigns its fingers accordingly. All messages are sent bydim-and-burst without muting. Each end of the communication link choosesthe best configuration on a frame-by-frame basis, with handofftransparent to users.

A cdma2000 system is a third-generation (3G) wideband; spread spectrumradio interface system that uses the enhanced service potential of CDMAtechnology to facilitate data capabilities, such as Internet andintranet access, multimedia applications, high-speed businesstransactions, and telemetry. The focus of cdma2000, as is that of otherthird-generation systems, is on network economy and radio transmissiondesign to overcome the limitations of a finite amount of radio spectrumavailability.

FIG. 3 illustrates a data link protocol architecture layer 20 for acdma2000 wireless network. The data link protocol architecture layer 20includes an Upper Layer 60, a Link Layer 30 and a Physical layer 21.

The Upper layer 60 includes three sublayers; a Data Services sublayer61; a Voice Services sublayer 62 and a Signaling Services sublayer 63.Data services 61 are services that deliver any form of data on behalf ofa mobile end user and include packet data applications such as IPservice, circuit data applications such as asynchronous fax and B-ISDNemulation services, and SMS. Voice services 62 include PSTN access,mobile-to-mobile voice services, and Internet telephony. Signaling 63controls all aspects of mobile operation.

The Signaling Services sublayer 63 processes all messages exchangedbetween the MS 2 and BS 6. These messages control such functions as callsetup and teardown, handoffs, feature activation, system configuration,registration and authentication.

The Link Layer 30 is subdivided into the Link Access Control (LAC)sublayer 32 and the Medium Access Control (MAC) sublayer 31. The LinkLayer 30 provides protocol support and control mechanisms for datatransport services and performs the functions necessary to map the datatransport needs of the Upper layer 60 into specific capabilities andcharacteristics of the Physical Layer 21. The Link Layer 30 may beviewed as an interface between the Upper Layer 60 and the Physical Layer20.

The separation of MAC 31 and LAC 32 sublayers is motivated by the needto support a wide range of Upper Layer 60 services and the requirementto provide for high efficiency and low latency data services over a wideperformance range, specifically from 1.2 Kbps to greater than 2 Mbps.Other motivators are the need for supporting high Quality of Service(QoS) delivery of circuit and packet data services, such as limitationson acceptable delays and/or data BER (bit error rate), and the growingdemand for advanced multimedia services each service having a differentQoS requirements.

The LAC sublayer 32 is required to provide a reliable, in-sequencedelivery transmission control function over a point-to-point radiotransmission link 42. The LAC sublayer 32 manages point-to pointcommunication channels between upper layer 60 entities and providesframework to support a wide range of different end-to-end reliable LinkLayer 30 protocols.

The Link Access Control (LAC) sublayer 32 provides correct delivery ofsignaling messages. Functions include assured delivery whereacknowledgement is required, unassured delivery where no acknowledgementis required, duplicate message detection, address control to deliver amessage to an individual MS 2, segmentation of messages into suitablesized fragments for transfer over the physical medium, reassembly andvalidation of received messages and global challenge authentication.

The MAC sublayer 31 facilitates complex multimedia, multi-servicescapabilities of 3G wireless systems with QoS management capabilities foreach active service. The MAC sublayer 31 provides procedures forcontrolling the access of packet data and circuit data services to thePhysical Layer 21, including the contention control between multipleservices from a single user, as well as between competing users in thewireless system. The MAC sublayer 31 also performs mapping betweenlogical channels and physical channels, multiplexes data from multiplesources onto single physical channels and provides for reasonablyreliable transmission over the Radio Link Layer using a Radio LinkProtocol (RLP) 33 for a best-effort level of reliability. SignalingRadio Burst Protocol (SRBP) 35 is an entity that provides connectionlessprotocol for signaling messages. Multiplexing and QoS Control 34 isresponsible for enforcement of negotiated QoS levels by mediatingconflicting requests from competing services and the appropriateprioritization of access requests.

The Physical Layer 20 is responsible for coding and modulation of datatransmitted over the air. The Physical Layer 20 conditions digital datafrom the higher layers so that the data may be transmitted over a mobileradio channel reliably.

The Physical Layer 20 maps user data and signaling, which the MACsublayer 31 delivers over multiple transport channels, into a physicalchannels and transmits the information over the radio interface. In thetransmit direction, the functions performed by the Physical Layer 20include channel coding, interleaving, scrambling, spreading andmodulation. In the receive direction, the functions are reversed inorder to recover the transmitted data at the receiver.

FIG. 4 illustrates an overview of call processing. Processing a callincludes pilot and sync channel processing, paging channel processing,access channel processing and traffic channel processing.

Pilot and sync channel processing refers to the MS 2 processing thepilot and sync channels to acquire and synchronize with the CDMA systemin the MS 2 Initialization State. Paging channel processing refers tothe MS 2 monitoring the paging channel or the forward common controlchannel (F-CCCH) to receive overhead and mobile-directed messages fromthe BS 6 in the Idle State. Access channel processing refers to the MS 2sending messages to the BS 6 on the access channel or the Enhancedaccess channel in the System Access State, with the BS 6 alwayslistening to these channels and responding to the MS on either a pagingchannel or the F-CCCH. Traffic channel processing refers to the BS 6 andMS 2 communicating using dedicated forward and reverse traffic channelsin the MS 2 Control on Traffic Channel State, with the dedicated forwardand reverse traffic channels carrying user information, such as voiceand data.

FIG. 5 illustrates the initialization state of a MS 2. TheInitialization state includes a System Determination Substate, PilotChannel Acquisition, Sync Channel Acquisition, a Timing Change Substateand a Mobile Station Idle State.

System Determination is a process by which the MS 2 decides from whichsystem to obtain service. The process could include decisions such asanalog versus digital, cellular versus PCS, and A carrier versus Bcarrier. A custom selection process may control System Determination. Aservice provider using a redirection process may also control Systemdetermination. After the MS 2 selects a system, it must determine onwhich channel within that system to search for service. Generally the MS2 uses a prioritized channel list to select the channel.

Pilot Channel Processing is a process whereby the MS 2 first gainsinformation regarding system timing by searching for usable pilotsignals. Pilot channels contain no information, but the MS 2 can alignits own liming by correlating with the pilot channel. Once thiscorrelation is completed, the MS 2 is synchronized with the sync channeland can read a sync channel message to further refine its timing. The MS2 is permitted to search up to 15 seconds on a single pilot channelbefore it declares failure and returns to System Determination to selecteither another channel or another system. The searching procedure is notstandardized, with the time to acquire the system depending onimplementation.

In cdma2000, there may be many pilot channels, such as OTD pilot, STSpilot and Auxiliary pilot, on a single channel. During SystemAcquisition, the MS 2 will not find any of these pilot channels becausethey are use different Walsh codes and the MS is only searching forWalsh 0.

The sync channel message is continuously transmitted on the sync channeland provides the MS 2 with the information to refine timing and read apaging channel. The mobile receives information from the BS 6 in thesync channel message that allows it to determine whether or not it willbe able to communicate with that BS.

In the idle State, the MS 2 receives one of the paging channels andprocesses the messages on that channel. Overhead or configurationmessages are compared to stored sequence numbers to ensure the MS 2 hasthe most current parameters. Messages to the MS 2 are checked todetermine the intended subscriber.

The BS 6 may support multiple paging channels and/or multiple CDMAchannels (frequencies). The MS 2 uses a hash function based on its IMSIto determine which channel and frequency to monitor in the Idle State.The BS 6 uses the same hash function to determine which channel andfrequency to use when paging the MS 2.

Using a Slot Cycle Index (SCI) on the paging channel and on F-CCCHsupports slotted paging. The main purpose of slotted paging is toconserve battery power in MS 2. Both the MS 2 and BS 6 agree in whichslots the MS will be paged. The MS 2 can power down some of itsprocessing circuitry during unassigned slots. Either the General Pagemessage or the Universal Page message may be used to page the mobile onF-CCCH. A Quick paging channel that allows the MS 2 to power up for ashorter period of time than is possible using only slotted paging onF-PCH or F-CCCH is also supported.

FIG. 6 illustrates the System Access state. The first step in the systemaccess process is to update overhead information to ensure that the MS 2is using the correct access channel parameters, such as initial powerlevel and power step increments. A MS 2 randomly selects an accesschannel and transmits without coordination with the BS 6 or other MS.Such a random access procedure can result in collisions. Several stepscan be taken to reduce the likelihood of collision, such as use of aslotted structure, use of a multiple access channel, transmitting atrandom start times and employing congestion control, for example,overload classes.

The MS 2 may send either a request or a response message on the accesschannel. A request is a message sent autonomously, such as anOrigination message. A response is a message sent in response to amessage received from the BS 6. For example, a Page Response message isa response to a General Page message or a Universal message.

An access attempt, which refers to the entire process of sending oneLayer 2 encapsulated PDU and receiving an acknowledgment for the PDU,consists of one or more access sub-attempts, as illustrated in FIG. 7.An access sub-attempt includes of a collection of access probesequences, as illustrated in FIG. 8. Sequences within an accesssub-attempt are separated by a random backoff interval (RS) and apersistence delay (PD). PD only applies to access channel request, notresponse. FIG. 9 illustrates a System Access state in which collisionsare avoided by using a slot offset of 0-511 slots.

The Multiplexing and QoS Control sublayer 34 has both a transmittingfunction and a receiving function. The transmitting function combinesinformation from various sources, such as Data Services 61, SignalingServices 63 or Voice Services 62, and forms Physical layer SDUs andPDCHCF SDUs for transmission. The receiving function separates theinformation contained in Physical Layer 21 and PDCHCF SDUs and directsthe information to the correct entity, such as Data Services 61, UpperLayer Signaling 63 or Voice Services 62.

The Multiplexing and QoS Control sublayer 34 operates in timesynchronization with the Physical Layer 21. If the Physical Layer 21 istransmitting with a non-zero frame offset, the Multiplexing and QoSControl sublayer 34 delivers Physical Layer SDUs for transmission by thePhysical Layer at the appropriate frame offset from system time.

The Multiplexing and QoS Control sublayer 34 delivers a Physical Layer21 SDU to the Physical Layer using a physical-channel specific serviceinterface set of primitives. The Physical Layer 21 delivers a PhysicalLayer SDU to the Multiplexing and QoS Control sublayer 34 using aphysical channel specific Receive Indication service interfaceoperation.

The SRBP Sublayer 35 includes the sync channel, forward common controlchannel, broadcast control channel, paging channel and access channelprocedures.

The LAC Sublayer 32 provides services to Layer 3 60. SDUs are passedbetween Layer 3 60 and the LAC Sublayer 32. The LAC Sublayer 32 providesthe proper encapsulation of the SDUs into LAC PDUs, which are subject tosegmentation and reassembly and are transferred as encapsulated PDUfragments to the MAC Sublayer 31.

Processing within the LAC Sublayer 32 is done sequentially, withprocessing entities passing the partially formed LAC PDU to each otherin a well-established order. SDUs and PDUs are processed and transferredalong functional paths, without the need for the upper layers to beaware of the radio characteristics of the physical channels. However,the upper layers could be aware of the characteristics of the physicalchannels and may direct Layer 2 30 to use certain physical channels forthe transmission of certain PDUs.

A 1xEV-DO system is optimized for packet data service and characterizedby a single 1.25 MHz carrier (“1x”) for data only or data Optimized(“DO”), Furthermore, there is a peak data rate of 2.4 Mbps or 3.072 Mbpson the forward Link and 153.6 Kbps or 1.8432 Mbps on the reverse Link.Moreover, a 1xEV-DO system provides separated frequency bands andinternetworking with a 1x System. FIG. 10 illustrates a comparison ofcdma2000 for a 1x system and a 1xEV-DO system.

In CDMA2000 there are concurrent services, whereby voice and data aretransmitted together at a maximum data rate of 614.4 kbps and 307.2 kbpsin practice. An MS 2 communicates with the MSC 5 for voice calls andwith the PDSN 12 for data calls. A cdma2000 system is characterized by afixed rate with variable power with a Walsh-code separated forwardtraffic channel.

In a 1xEV-DO system, the maximum data rate is 2.4 Mbps or 3.072 Mbps andthere is no communication with the circuit-switched core network 7. A1xEV-DO system is characterized by fixed power and a variable rate witha single forward channel that is time division multiplexed.

FIG. 11 illustrates a 1xEV-DO system architecture. In a 1xEV-DO system,a frame consists of 16 slots, with 600 slots/sec, and has a duration of26.67 ms, or 32,768 chips. A single slot is 1.6667 ms long and has 2048chips. A control/traffic channel has 1600 chips in a slot, a pilotchannel has 192 chips in a slot and a MAC channel has 256 chips in aslot. A 1xEV-DO system facilitates simpler and faster channel estimationand time synchronization.

FIG. 12 illustrates a 1xEV-DO default protocol architecture. FIG.illustrates a 1xEV-DO non-default protocol architecture.

Information related to a session in a 1xEV-DO system includes a set ofprotocols used by an MS 2, or access terminal (AT), and a BS 6, oraccess network (AN), over an airlink, a Unicast Access TerminalIdentifier (UATI), configuration of the protocols used by the AT and ANover the airlink and an estimate of the current AT location.

The Application Layer provides best effort, whereby the message is sentonce, and reliable delivery, whereby the message can be retransmittedone or more times. The stream layer provides the ability to multiplex upto 4 (default) or 255 (non-default) application streams for one AT 2.

The Session Layer ensures the session is still valid and manages closingof session, specifies procedures for the initial UATI assignment,maintains AT addresses and negotiates/provisions the protocols usedduring the session and the configuration parameters for these protocols.

FIG. 14 illustrates the establishment of a 1xEV-DO session. Asillustrated in FIG. 14, establishing a session includes addressconfiguration, connection establishment, session configuration andexchange keys.

Address configuration refers to an Address Management protocol assigninga UATI and Subnet mask. Connection establishment refers to ConnectionLayer Protocols setting up a radio link. Session configuration refers toa Session Configuration Protocol configuring all protocols. Exchange keyrefers a Key Exchange protocol in the Security Layer setting up keys forauthentication.

A “session” refers to the logical communication link between the AT 2and the RNC, which remains open for hours, with a default of 54 hours. Asession lasts until the PPP session is active as well. Sessioninformation is controlled and maintained by the RNC in the AN 6.

When a connection is opened, the AT 2 can be assigned the forwardtraffic channel and is assigned a reverse traffic channel and reversepower control channel. Multiple connections may occur during singlesession.

The Connection Layer manages initial acquisition of the network andcommunications. Furthermore, the Connection Layer maintains anapproximate AT 2 location and manages a radio link between the AT 2 andthe AN 6. Moreover, the Connection Layer performs supervision,prioritizes and encapsulates transmitted data received from the SessionLayer, forwards the prioritized data to the Security Layer anddecapsulates data received from the Security Layer and forwards it tothe Session Layer.

FIG. 15 illustrates Connection Layer Protocols. As illustrated in FIG.16, the protocols include an Initialization State, an Idle State and aConnected State.

In the initialization State, the AT 2 acquires the AN 6 and activatesthe initialization State Protocol. In the Idle State, a closedconnection is initiated and the Idle State Protocol is activated. In theConnected State, an open connection is initiated and the Connected StateProtocol is activated.

A closed connection refers to a state where the AT 2 is not assigned anydedicated air-link resources and communications between the AT and AN 6are conducted over the access channel and the control channel. An openconnection refers to a state where the AT 2 can be assigned the forwardtraffic channel, is assigned a reverse power control channel and areverse traffic channel and communication between the AT 2 and AN 6 isconducted over these assigned channels as well as over the controlchannel.

The Initialization State Protocol performs actions associated withacquiring an AN 6. The idle State Protocol performs actions associatedwith an AT 2 that has acquired an AN 6, but does not have an openconnection, such as keeping track of the AT location using a RouteUpdate Protocol. The Connected State Protocol performs actionsassociated with an AT 2 that has an open connection, such as managingthe radio link between the AT and AN 6 and managing the proceduresleading to a closed connection. The Route Update Protocol performsactions associated with keeping track of the AT 2 locution andmaintaining the radio link between the AT and AN 6. The Overhead MessageProtocol broadcasts essential parameters, such as QuickConfig,SectorParameters and AccessParameters message, over the control channel.The Packet Consolidation Protocol consolidates and prioritizes packetsfor transmission as a function of their assigned priority and the targetchannel as well as providing packet de-multiplexing on the receiver.

The Security Layer includes a key exchange function, authenticationfunction and encryption function. The key exchange function provides theprocedures followed by the AN 2 and AT 6 for authenticating traffic. Theauthentication function provides the procedures followed by the AN 2 andAT 6 to exchange security keys for authentication and encryption. Theencryption function provides the procedures followed by the AN 2 and AT6 for encrypting traffic.

The 1xEV-DO forward Link is characterized in that no power control andno soft handoff is supported. The AN 6 transmits at constant power andthe AT 2 requests variable rates on the forward Link. Because differentusers may transmit at different times in TDM, it is difficult toimplement diversity transmission from different BS's 6 that are intendedfor a single user.

In the MAC Layer, two types of messages originated from higher layersare transported across the physical layer, specifically a User datamessage and a signaling message. Two protocols are used to process thetwo types of messages, specifically a forward traffic channel MACProtocol for the User data message and a control channel MAC Protocol,for the signaling message.

The Physical Layer is characterized by a spreading rate of 1.2288 Mcps,a frame consisting of 16 slots and 26.67 ms, with a slot of 1.67 ms and2048 chips, The forward Link channel includes a pilot channel, a forwardtraffic channel or control channel and a MAC channel.

The pilot channel is similar to the to the cdma2000 pilot channel inthat it comprises all “0” information bits and Walsh-spreading with WOwith 192 chips for a slot.

The forward traffic channel is characterized by a data rate that variesfrom 38.4 kbps to 2.4576 Mbps or from 4.8 kbps to 3.072 Mbps. PhysicalLayer packets can be transmitted in 1 to 16 slots and the transmit slotsuse 4-slot interlacing when more than one slot is allocated. If ACK isreceived on the reverse Link ACK channel before all of the allocatedslots have been transmitted, the remaining slots shall not betransmitted.

The control channel is similar to the sync channel and paging channel incdma2000. The control channel is characterized by a period of 256 slotsor 427.52 ms, a Physical Layer packet length of 1024 bits or 128, 256,512 and 1024 bits and a data rate of 38.4 kbps or 76.8 kbps or 19.2kbps, 38.4 kbps or 76.8 kbps.

The 1xEV-DO reverse link is characterized in that the AN 6 can powercontrol the reverse Link by using reverse power control and more thanone AN can receive the AT's 2 transmission via soft handoff.Furthermore, there is no TDM on the reverse Link, which is channelizedby Walsh code using a long PN code.

An access channel is used by the AT 2 to initiate communication with theAN 6 or to respond to an AT directed message. Access channels include apilot channel and a data channel.

An AT 2 sends a series of access probes on the access channel until aresponse is received from the AN 6 or a timer expires. An access probeincludes a preamble and one or more access channel Physical Layerpackets. The basic data rate of the access channel is 9.6 kbps, withhigher data rates of 19.2 kbps and 38.4 kbps available.

When more that one AT 2 is paged using the same Control channel packet,Access Probes may be transmitted at the same time and packet collisionsare possible. The problem can be more serious when the AT's 2 areco-located, are in a group call or have similar propagation delays.

One reason for the potential of collision is the inefficiency of thecurrent persistence test in conventional methods. Because an AT 2 mayrequire a short connection setup time, a paged AT may transmit accessprobes at the same time as another paged AT when a persistence test isutilized.

Conventional methods that use a persistence test are not sufficientsince each AT 2 that requires a short connection setup times and/or ispart of a group call may have the same persistence value, typically setto 0. If AT's 2 are co-located, such as In a group call, the AccessProbes arrive at the An 6 at the same time, thereby resulting in accesscollisions and increased connection setup time.

Therefore, there is a need for a more efficient approach for accessprobe transmission from co-located mobile terminals requiring shortconnection times. The present invention addresses this and other needssuch as interference cancellation.

In a wireless communication system having multiple antennas, a feedbackchannel (or feedback information) can be used for by a receiving end(e.g., access terminal, mobile station, or mobile terminal) to reportthe channel condition regarding one or more forward links (or sometimes,reverse links). The feedback information can include the channelcondition/quality for the best serving sector and/or carrier(sub-carrier) and/or antenna as well as any combination of these havingthe strongest signal. In order for a transmitting end (e.g., accessnetwork, base station, or Node B) to take advantage of forward link orreverse link frequency diversity, the receiving end can have a specifiednumber, N, of carriers (sub-carriers) assigned and report the channelconditions on N number of feedback channels.

In the wireless communication system (e.g., code division multipleaccess 2000 evolution data only (EV-DO) system), at least one antennacan be located per cell/sector. Furthermore, the at least one antennacan be located in the receiving end. EV-DO offers fast packetestablishment on both the forward and reverse links along with airinterface enhancements that reduce latency and improve data rates.

FIG. 16 is an exemplary diagram illustrating transmission of pilotsignal and feedback information between a single transmitting end and asingle receiving end. However, a number of transmitting end and a numberof receiving end as well as a number of carriers (sub-carriers),antennas, and/or sector(s)/cell(s) are not limited to one.

In transmitting data from at least one user, the transmitting endtypically sends pilots or pilot signals via all available antennas andsub-carriers to at least one receiving end. In response, the receivingend sends back feedback information regarding the channelcondition/quality of each sub-carrier including the antenna(s). Based onthe feedback information, the transmitting end determines thecarrier/antenna combination for transmitting the data or data packets.The feedback information can be transmitted periodically as well asaperiodically.

Even if the data packets are transmitted based on the feedbackinformation provided from the receiving end(s), the transmittedsub-packet may not be received and decoded accurately. To address thisissue, an automatic request (ARQ) or an hybrid-ARQ (HARQ) can be used.In ARQ or HARQ, data packets or sub-packets are usually re-transmitted.However, if the re-transmission of the sub-packet(s) takes place via thesame carrier/antenna used to transmit the previous/original packet(s),then there is a chance that re-transmitted sub-packet(s) may or may notbe received accurately again, especially, if the channel condition isbad.

With respect to re-transmission, based on the CQI and/or acknowledgementof the previous sub-packet transmission, the same carrier/antenna ordifferent carrier/antenna can be used for the transmission of subsequentsub-packet(s). Therefore, subsequent (or simultaneous) sub-packets canbe transmitted on same carriers (or a set of tones) or antenna; ordifferent cells/sectors. As discussed, antennas can be referred to ascells/sectors.

This is valuable in that power can be saved, the chance of earlytermination can be maximized, or the delay can be minimized. Here,multiple carriers (or tones) and/or antennas are assumed.

To this end, a forward link (FL) overhead channel can be used to carryinformation, indicating the carrier, frequency tones, or antennas, forthe associated sub-packet. In other words, the overhead channel can beused to provide which carrier/antenna has been selected by thetransmitting end to carry the subsequent sub-packets. Again, thedecision by the transmitting end can be based on the CQI and/oracknowledgement of the previous sub-packet transmission.

One of the reasons for providing the selected carrier/antennacombination via the overhead channel is so that the receiving end canknow which carrier and antenna to look to for re-transmission of thesub-packets. Consequently, such information can help in receiving anddecoding the sub-packet(s).

Alternatively, the sub-packets (subsequent, different antennas, orcarriers) can be sent with different transmission formats. In otherwords, the sub-packets can be modulated differently using differentmodulation schemes. The transmission format of a subsequentlytransmitted sub-packet may be different from the transmission format ofthe previous sub-packet, based on the most updated CQI.

For example, the previous transmission is made using a specifiedmodulation scheme (e.g, quadrature phase shin keying (QPSK) with aspecified code rate). However, based on the CQI, the next transmissioncan be made using a different modulation scheme which can result insuccessful reception/demodulation. As such, the subsequent transmissioncan be made using a different format or modulation scheme (e.g., binaryphase shift keying (BPSK)).

Since the overhead channel is transmitted with the sub-packettransmission, the current sub-packet can be transmitted using thedifferent transmission format used in the transmission of the previoussub-packet. For example, if the channel quality is favorable, then thesub-packet with a shorter duration, higher modulation, and coding can betransmitted.

As another alternative for re-transmission, the sub-packets can be senton more than one carrier/antenna simultaneously.

In a wireless communication system, a transmitting side (e.g., accessnetwork) can send data to a receiving side (e.g., access terminal). Ifthe receiving side is located near a cell/sector edge region, the datatransmitted from the transmitting side may experience difficulty, due tofactors such as low receive power and/or interference, in receiving thedata. The same difficulties may be experienced in multi-cell/sectorenvironments where interference can be encountered from neighboringcells/sectors, and in particular, during handover/handoff situations.FIG. 17 is an exemplary diagram illustrating handover situation.

By using the combinations of selected carriers and antennas, the userscan be provided with high and more reliable data transmission in arelatively good channel condition. In addition, the users having badchannel condition can benefit as well.

To address such problems of above, a carrier and/or antenna and/orsector/cell having the best channel condition or channel quality can beselected for transmission. To this end, the receiving side needs toprovide feedback information to the transmitting side regarding whichcarrier/antenna out of plurality of carriers/antennas has the bestchannel condition/quality. The channel condition can be measured basedon a pilot sent from the transmitting side to the receiving side, forexample. Using the feedback (e.g., channel quality information (CQI) ora data rate control (DRC)), the transmitting side can choose thecarrier, antenna, or sector/cell as well and any combination thereof fortransmitting the data. Additionally, the sector/cell can have at leastone antenna element.

The feedback information can be transmitted periodically as well asaperiodically. With periodic or aperiodic feedback, the transmitting endcan select better carrier/antenna/sector combinations than from theprevious transmission. Due to susceptibility of transmission successesand failures depending on channel conditions, periodic or aperiodicfeedback information provides the transmitting end to adapt or adjust tothe changing channel conditions for better transmission of data.

Based on the feedback information from the receiving end, the feedbackinformation can include a selection by the receiving end as to whichcombination of antenna(s) and carrier(s) for transmission. To putdifferently, the receiving end can indicate or point to the combinationprovided in a sub-active set.

The sub-active set can be described as an index of different carrier(sub-carrier) and antenna combinations. For example, in a system havingtwo (2) sub-carriers (e.g., Sub-carrier #1 and Sub-carrier #2) and two(2) antennas (e.g., Antenna #1 and Antenna #2), the possiblecombinations can be as follows. Here, the index has four (4) differentcombinations. Index 1 indicates a combination of Sub-carrier #1 andAntenna #1, index 2 indicates a combination of Sub-carrier #1 andAntenna #2, index 3 indicates a combination of Sub-carrier #2 andAntenna #1, and index 4 indicates a combination of Sub-carrier #2 andAntenna #2. Based on the channel condition/quality, the receiving endselects any one or at least one of the index/indices and feedbacks itsselection to the transmitting end. In short, the sub-active set providesinformation regarding which carrier and/or antenna has better channelcondition.

For example, if the channel condition/quality of the pilot transmittedvia Antenna #2/Sub-carrier #1 has the strongest signal or has the bestchannel condition, the sub-packet can be transmitted via Antenna#2/Sub-carrier #1.

Further, the size of the index depends on the number of carriers andantennas that are available in the system. Moreover, it is possible toselect a pair of antennas as well as a pair of carrier/sub-carriers.

In making the selection for the optimum carrier/antenna combination, thereceiving end can use the pilots sent from the transmitting end. Forexample, in a multiple antenna system, the transmitting end cansimultaneously send different types of pilots, Type A and Type B, viaAntenna #1 and Antenna #2. In other words, both Type A and Type B pilotsare transmitted on different sub-carriers to the receiving end viaAntenna #1, and similarly, both Type A and Type B pilots are transmittedon different sub-carriers to the receiving end via Antenna #2. Based onthe channel condition, the receiving end can select Type A pilot forhaving better channel condition for Antenna #1 while selecting Type Bfor Antenna #2. The feedback as to which type pilot (Type A or Type B)is better is provided to the transmitting end per antenna.

Through the sub-active set, the receiving side can point to (orindicate) the carrier/antenna having the best channel condition. Putdifferently, the CQI channel can point to a carrier(s)/antenna(s) in thesub-active set. The same concept can also be applied to sectors/cellswith respect to carriers/antennas. That is, the receiving end canprovide which carrier or sub-carrier has better transmit quality, andwhich sector/cell has better channel condition. As discussed, theantenna can also be referred to as sector/cell.

Further, a number of sub-active sets can correspond to the number ofassigned carriers. In a single antenna selection, the receiving end canbe assigned a specified number of sub-carrier(s) per antenna. Based onthe channel condition, the receiving end provides which sub-carrier perantenna has a better or best channel quality. For example, if three (3)sub-carriers are assigned to the receiving end, then there can be up tothree (3) sub-active sets.

If the receiving end is in soft handoff/handover, a combined CQI channelcan be used as a sub-active set. That is, similar to above, the combinedCQI channel can point or indicate to one or a set of antennas among allcarriers/antennas. For example, if space-time coding (STC) with two (2)transmitter antennas is used for a forward link (FL) transmission, andeach sector has N number of antennas sending type-A pilots and M numberof antennas sending type-B pilots, then two (2) CQI channels, one foreach type, can be used as the combined feedback channel for thesub-active set. The access terminal (AT) is constrained to point thesetwo (2) channels to the antennas which have the same data source.

In providing the feedback information, the selection of combinations ofcarriers and antennas can be interlaced. The interlaces can becategorized into an odd interlace(s) and an even interlace(s). Forexample, the odd interlaces can provide channel quality/condition of thetransmit channels. Here, the odd interlaces can serve the functionsimilar to that of a data rate control (DRC) value (e.g., CQI value)through which the channel quality is provided. At the same time, theeven interlaces can be used to provide the selected antenna. Here, theeven interlaces can serve the function similar to that of the selectedindex which is described above. These odd and even interlaces arecombined to form a set of interlaces and provided to the transmittingend to inform as to which combination of carrier/antenna.

Further, the feedback information can be provided in form of a CQIcover. Traditionally, the CQI cover can be used to point to thereceiving end (e.g., access network or base station). Here, the CQIcover can be used to provide information regarding the sub-carrier aswell as the antenna selected by the receiving end. To put differently, anumber of bits for the CQI cover can be extended/increased to include asector identification and selected antenna. Further, the extended CQIcover can include the sector identification and the selected antenna aswell as the information equivalent to the CQI value. Here, the CQI valueremains unchanged while the CQI cover changes to include the informationon the sector identification and the antenna(s).

Simply put, the number of bits of the CQI cover can be extended suchthat the cover represents selected antennas which can be in the same ordifferent sectors/cells. If there is more than one transmitting end,then the extended CQI cover can include the selection of thetransmitting end in addition to the selection of carrier/antennacombination. Similarly, the CQI cover can further include the CQI value.

As an alternative method of providing the feedback information, a numberof bits for the CQI value can be extended or increased. If a specifiednumber of bits are used to indicate the CQI value, four (4) bits, forexample, a number of bits can be added, two (2) bits for example. Inother words, instead of using four (4) bits, as conventionally used, atotal of six (6) bits can be used for the DRC value. Hence, four (4)bits can be used to for the original or conventional purpose, and theextended/added two (2) bits can be used to indicate the antennaselection. Here, the CQI cover remains unchanged (e.g., sectoridentification) while the CQI value changes.

As the number of bits of the CQI value can be extended to include theinformation of the selected antenna(s), the extended CQI value canrepresent selected antenna indices and CQI index pair. Moreover, inselecting the antennas, more than two antennas can be selected based onthe channel conditions.

As another alternative of providing feedback information, a differentialvalue can be used. In other words, instead of providing a full CQI valueevery time, a differential value relative to the previous value can beprovided. More specifically, a full CQI value is initially provided sothat a reference can be determined. Using the full CQI value as thereference, subsequent transmissions include differential value. Forexample, the subsequent differential value can indicate “up or down” sothat the transmitting end can either increase or decrease relative tothe previous value. With this arrangement, the transmission power forthe CQI channel can be reduced.

For example, regarding multiple CQI channels, one anchor CQI channel cansend a full CQI value while the other CQI channel sends a differentialvalue relative to the full CQI value of the other channel in reportingits full CQI value. Here, one of a plurality of carriers (or antennas)can be an anchor carrier while other carriers are dependent on theanchor carrier. The assumption here is that there is not much variationbetween carriers. Alternatively, each CQI channel can send a full CQI

As discussed above with respect to handoff/handover situations, therecan be multiple transmitters at the transmitting side. In situationsrelated to soft, softer, or even softest handoffs, multiple CQIs can beused to transmit a CQI to each transmitter (transmitting sector in theactive set). Further, multiple power control commands (basicallyequivalent to differential CQI) can be sent to each transmitter. Inaddition, the power level of the different CQIs can be different and canbe controlled separately by each sector. In other words, the differencein power levels are based on the power command from each transmitter.The transmitter can be any one of a base station, access network, NodeB, network, mobile station, mobile terminal, and access terminal.

With respect to various techniques regarding feedback, these techniquescan be applied to spatial multiplexing. In order for spatialmultiplexing to come in effect, there are at least two (2) antennas atthe transmitting end. Moreover, the transmitting end and/or thereceiving ends may be in different sectors/cells.

Further, with respect to spatial multiplexing, the receiving end cansend code (rank) selection to the transmitting end. The code (rank)selection refers to a number of carriers/antennas available fortransmission. Here, at least two (2) CQIs can be sent to thetransmitting end, and the code (rank) selection provides informationregarding a number of channels as well as sizes of each channel.Thereafter, the CQI is used to identify how much data can be transmittedon the carrier. For example, if there are two carriers, two (2) CQIs areneeded, one for each CQI. As another example, the code index and the CQIfor the code index. Parallel CQI channels can be indicated by codeindices and the corresponding CQI value.

As discussed above, multiple channels can be used to provide feedbackinformation to the transmitting end, especially, in multiple antennaenvironment. Further, the transmitting end (e.g., access network) canuse the feedback information to select the best channel (orcarrier/antenna) for transmitting the data. As another form of feedbackinformation, the CQI can be used.

In the CQI, the receiving end includes information on whichcarrier/antenna has the best channel quality and frequency pair (pilot)based on the transmission from the transmitting end. As discussed, theCQI can also be substituted by a data rate control (DRC).

FIG. 18 is an exemplary diagram illustrating selection of a pilot by thereceiving end for multiple sectors. More specifically, referring to FIG.18, the receiving end selects a pilot in sector 1 (S1) on frequency 2(12) out of six (6) pilots as its FL server with a single feedbackchannel. Here, the receiving end is assumed to be capable of monitoringpilots on different carriers simultaneously. The CQI cover can be usedto select the sector or distinguish different sectors. Moreover, the CQIcover is the same for all sectors.

An alternative description of FIG. 18 is FIG. 19. FIG. 19 is anotherexemplary diagram illustrating selection of a pilot by the receiving endfor multiple sectors. In FIG. 19, there are three (3) sub-carrieslabeled f1, f2, and f3. Moreover, there are two antennas or sectors, Aand B. As shown in the figure, the sub-carrier is selected where theselected sub-carrier applies to both antennas/sectors A and B. There arethree (3) feedback channels here per sub-carrier (e.g., f1, f2 and f3).Figuratively, the sub-carrier is selected horizontally. Here, theselection made can be referred to as a sub-active set, the details ofwhich are described above. In other words, the receiving end can use thefeedback information (e.g., CQI) to make the selection.

FIG. 20 is an exemplary diagram illustrating selection of a pilot by thereceiving end for a single sector. Referring to FIG. 20, the CQI coveris used to distinguish different carriers, and the CQI cover isdifferent for each sector/antenna. Figuratively, the sub-carrier can beselected vertically. Here, there is one feedback channel whereas in FIG.19, there are three feedback channels. Similarly, the feedbackinformation (e.g., CQI) can be used by the receiving end to make theselection.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A method of transmitting feedback information at a user equipment(UE) in a multi-carrier wireless communication system, the methodcomprising: receiving information related to a link between a firstforward link carrier and a first reverse link carrier, wherein the firstforward link carrier is used to receive data from a base station, andwherein the first reverse link carrier is used to transmit data to thebase station; receiving information related to a link between a secondforward link carrier and a second reverse link carrier, wherein thesecond forward link carrier is used to receive data from the basestation, and wherein the second reverse link carrier is used to transmitdata to the base station; receiving signals via the first forward linkcarrier and the second forward link carrier from the base station; andtransmitting feedback information for the first forward link carrier andthe second forward link carrier, wherein the feedback information istransmitted through a feedback channel of a single reverse link carrier,and wherein the first forward link carrier and the second forward linkcarrier are different.
 2. The method of claim 1, wherein the feedbackchannel a control charm
 3. The method of claim 2, wherein the feedbackinformation comprises channel state information (CSI) for the firstforward link carrier and the second forward link carrier.
 4. The methodof claim 2, wherein the feedback information comprises hybrid automaticrepeat request (HARQ) feedback information corresponding to the signalsreceived via the first forward link carrier and the second forward linkcarrier.
 5. The method of claim 1, wherein the feedback informationcomprises information of at least one combination of a carrier, anantenna and a sector, and information indicating a best pilot typecorresponding to each antenna of the at least one combination from amongpredefined pilot types, and wherein the at least one combination has thebest channel condition.
 6. A method of receiving feedback information ata base station (BS) in a multi-carrier wireless communication system,the method comprising: transmitting information related to a linkbetween a first forward link carrier and a first reverse link carrier,wherein the first forward link carrier is used to transmit data from thebase station and the first reverse link carrier is used to receive dataat the base station; transmitting information related to a link betweena second forward link carrier and a second reverse link carrier, whereinthe second forward link carrier is used to transmit data from the basestation and the second reverse link carrier is used to receive data atthe base station; transmitting signals via the first forward linkcarrier and the second forward link carrier to a user equipment (UE);and receiving feedback information for the first forward link carrierand the second forward link carrier from the UE, wherein the feedbackinformation is received through a feedback channel of a single reverselink carrier, and wherein the first forward link carrier and the secondforward link carrier are not different.
 7. The method of claim 6,wherein the feedback channel control channel.
 8. The method of claim 7,wherein the feedback information comprises channel state information(CSI) for the first forward link carrier and the second forward linkcarrier.
 9. The method of claim 7, wherein the feedback informationcomprises hybrid automatic repeat request (HARQ) feedback informationcorresponding to the signals transmitted via the first forward linkcarrier and the second forward link carrier.
 10. The method of claim 6,wherein the feedback information comprises information of at least onecombination of a carrier, an antenna and a sector, and informationindicating a best pilot type corresponding to each antenna of the atleast one combination from among predefined pilot types, and wherein theat least one combination has the best channel condition.